How to Install a Mantel on a Masonry Wall

Follow label directions to assemble the mantel kit, which typically includes a horizontal shelf supported by a vertical leg on either side. Attach the legs to the underside of the shelf using the provided hardware so they are tight.

Assign a helper to hold the mantel straight against the wall above the fireplace. Check that the mantel is level, or adjust as required.

Trace a line along the mantel’s upper edge with pencil to serve as a guideline on the wall for the horizontal cleat. Carefully set the mantel aside.

Measure the width of the shelf or mantel from inside. Cut a length of 2-by-4-inch lumber to the measurement using a handsaw. This lumber forms the horizontal mounting cleat that attaches the mantel to the wall. Repeat the process to cut two vertical mounting cleats for the sides or legs of the mantel.

Position the horizontal cleat on the wall so it will be concealed inside the fireplace mantel when attached. Measure and mark the mantel’s thickness on the wall, under the horizontal pencil guideline you made, and position the cleat along the lower line. Draw another horizontal line on the wall to form a guideline for the cleat.

Bore evenly spaced 1/2-inch pilot holes through the cleat and the masonry wall using a drill with masonry bit. Drive a concrete screw through each hole in the cleat to secure it to the wall. Repeat the process to secure the vertical cleats to the wall, on each side of the fireplace.

Mount the mantel directly on top of the three cleats, ensuring its back edges fall flush with the wall. The top of the mantel should fall flush against the first pencil guideline you formed.

Attach the mantel to the horizontal and vertical cleats, using evenly spaced 2-inch finish screws along the back edges. Cover the screw heads with wood putty, and touch-up with paint when they cure.